The present invention relates to electronic data processing, and more particularly concerns a physically small test instrument for checking input/output ports and cables of a data-processing system.
Modern data-processing systems of the mid-range and mainframe varieties are connected to dozens or even hundreds of users simultaneously by means of terminals remote from the processor unit itself. "Remote" may range from a few meters to hundreds of meters for a terminal directly attached via baseband cable, or to hundreds or thousands of kilometers for terminals attached via communications facilities such as telephone lines or satellite links.
Attachments between terminals and their processing system are prone to failure. They use inherently flaky components such as wiring and connectors. The wiring frequently extends through building structures in locations which are difficult to inspect. The attachments are often modified and rearranged by users and other non-professionals.
Checking out the input/output (I/O) ports of a DP system has been difficult in the past because it involves checking both ends of long and hidden cables for continuity, attaching terminals and other I/O or peripheral devices to the central processor by alternate means, and other activities requiring large amounts of time and effort.